The residual C2 domain of NEDD4-2s is sufficient to transfer the ability to rescue HIV-1_ΔPTAPP.

<p>(<b>A</b>) The transfer of NEDD4-2s sequences upstream of the first WW domain to WWP1 is sufficient to confer activity in the ΔPTAPP rescue assay. (<b>B</b>) Human ITCH and yeast Rsp5 potently rescue HXBH10_ΔPTAPP when their C2 domain is replaced by the residual C2 domain of NEDD4-2s. 293T cells were transfected with HXBH10_ΔPTAPP (1 µg) and vectors (2 µg each) expressing the indicated FLAG-tagged parental or chimeric ubiquitin ligase constructs, or the empty vector. Virion pellets and the cell lysates were analyzed by Western blotting to detect Gag, Gag cleavage products, and FLAG-tagged proteins as indicated.